VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Throw out bearing wear

I have a 1932 Chevy Confederate Roadster and I recently installed a new (rebuilt) cultch, throw out bearing and bearing plate which I acquired from the Filling Station. After only 60 miles the throw out bearing has worn down as can be seen from the pics the bearing has worn at an angle and I can no longer disengage the cultch to ship gears, what has caused this problem?

Clutch adjustment. When disengaged the TO bearing should not be touching the plate it rides agsinst.

Although not as quickly as yours, I wore out the carbon throw out bearing in my 1936 truck by having it adjusted improperly.

Mike

I agree that it appears as thought the face of the throw out bearing was always riding against the clutch lever arms.

I expect that the tips of the arms are worn also.

After you replace the worn parts adjust the clutch so there is about 1” free play on the clutch pedal.

I know this sounds crazy. Is the clutch arm return spring connected properly and strong enough to move the clutch pedal to the top of its travel?

Rusty,
There is a thrust plate (on the left in his photo) that attaches to the 3 levers on the pressure plate. This what the carbon bearing contacts when the clutch is disengaged. It is odd to me that so much wear is evident on the thrust plate, even if the plate and bearing were in constant contact.
I have NOS bearings and thrust plates. I have used and sold some from my stash but never had a bad result.

Mike

Hi Mike,

I agree that the angle of the wear on the bearing face is a bit of a mystery to me. My best guess is that the bearing was not rotating freely on the pivot points in the clutch arm.

The wear on the collar is definitely unusual

I am a little confused because I think we are looking at 2 different throwout bearings. One is the traditional carbon cast bearing that you soak in gear lube. Then he is showing a rotating element bearing.

If the rotating element one is frozen that would cause the extreme wear in the plate. That rotating face is a hardened bearing race.

Rusty,
There is only one bearing. The other item is the thrust plate. The thrust plate rotates with the flywheel, the carbon ring rubs it when the clutch pedal is pushed. I think the thrust plate is just cast iron with a surface that has been machined smooth.
I see no evidence that the cast portion of the t.o.b. has come in contact with the thrust plate. It looks like the excessive wear on the plate is caused by the carbon only.
Reedster has the parts captioned/identified in his photo.

Mike

Sorry that I am still confused. I agree that there is a regular carbon bearing in most of the pictures.

I see a “lubrolife” bearing that does not have the oiling cup in the picture with the worn thrust plate.

Hi Rusty

I noticed the same thing. You are not confused.
He has pictures of 2 different throw out bearings in his original post.

I also notice that BOTH of the bearings show at least some signs of the outer edge having rubbed on the thrust plate ON ONE SIDE.
If you look closely, you will also notice that the thrust plate wear IS NOT CENTERED on the plate or concentric as it should be.
This is in ADDITION to the wear being largely on one side of the bearing.

The non-concentric wear tells me something bigger than just the bearing and thrust plate are involved here.
Possibly a huge bell housing misalignment issue?

Things like this are so much easier when you can have eyes on the whole "global" situation. 🙂

PS
You will also notice there is a dark area on the face of the carbon surface on the original style bearing with the oil cup.
That dark ring is ALSO not concentrically marked on the bearing surface.

Hi Mike,

Good eyes to catch the eccentric wear pattern on the thrust plate.

I agree that there is more going on here than we can determine from these pictures.

Would the bell housing misalignment also create an off-center load on the throwout bearing? Would that lead to the angular wear pattern?

I'm still trying to "3D visualize" something that might create all of these effects. 🙂

Bell housings were cast iron by 1932, correct?
If so, I wouldn't think you could get one that far out of alignment.
And it would cause huge issues with the transmission input shaft and clutch splines.

The original style bearing looks to have been off center even before he changed to the new style.
Maybe a release fork issue?
Maybe the wrong fork?

I don't think the thrust plate could have looked the way it does while the old bearing was in it.
The groove is just too deep.
So most or all of the groove there must have happened after the new bearing was installed.
That suggests 1 of 2 things to me.

Either the new bearing is seized and not rotating...
(but that should show as radial grooves and tearing on the face of the bearing, which isn't there)

or

The release fork is holding the throw out bearing so far off center that it is "scrubbing" the surface of the thrust plate when the clutch is released.

Whatever the problem...
I wonder what this thing sounded like with the clutch pedal pushed down? 🙂

I think you need to inspect the 3 levers in the clutch pressure plate assembly. The part number you have quoted for the worn plate is correct for 1932, so you do not have anything but the correct 3 lever clutch pressure plate, assembly.

I think one lever is worn more than the other 2, . One lever may be not moving freely, or 2 or more pressure plate levers are not moving freely.

I suggest remove the pressure plate assembly and inspect those three levers and associated parts.

It is not uncommon for these bearings to be worn more on one side than on the other. I'm not saying it is normal, only that (to quote Tom Jones) "it's not unusual". The pivot ball might be adjusted improperly and contributing to the problem.

Ole, There is nothing that rotates on the carbon t.o.b. It just rubs the machined surface of the thrust plate to disengage the clutch. There is nothing to seize on the bearing.

Mike

Hi Mike

Rusty and I have noticed that there are TWO DIFFERENT bearings pictured above.
The one pictured beside the thrust collar is labelled as and looks like a Lubro-Life CH-33B.

As far as I know, that should be a replacement ball bearing style bearing.

It would be nice if the OP came back and clarified a few things as this problem seems to be a little confused and confusing.

From the pictures Reedster 101 shows, the top picture is a cast iron throw out bearing housing with the pressed in carbon wear ring. The bottom picture shows the throw out bearing plate on the left side and the Master Lubro Life CH-33B cast iron throw out bearing housing with a pressed in ball bearing throw out bearing. Both of these pictures show that the throw out bearings were run tight with no running clearance. The uneven wear is probably a worn clutch lever or the levers not adjusted properly which causes the throw out bearing plate to run at an angle and wobble. If this person purchased the Lubro Life CH-33B in the last few years, then it may have come from us as I purchased a lot of throw out bearing a few years back and 14 of these were the Master Lubro Life bearings. Everyone that I got feedback from said these Lubro Life throw out bearings worked great. Also from the pictures of the throw out bearings being run tight is what probably caused the short clutch disc life as the clutch disc was not totally engaged. The extreme wear shown on the throw out bearing plate would be caused by the ball bearing as it does have a hardened steel face and from the looks of it by the bluing of the bearing face, the grease probably got cooked out of the bearing causing it to lock up causing the extreme plate wear.

I want to thank everyone for their input on this problem and I finally had the time to investigate what has gone wrong and I think the problem occurred because the CLUTCH FORK RETAINER SPRING CLIP came off of the Fork Ball Stud which caused the fork and the throw out bearing to move around etc.
I did check the installation of the throw out bearing plate and other items as suggested and all appeared to be correct.
Finally after reinstallation of several new parts (including making sure the ball stud retainer spring clip was set properly width-in the grooves) it appears I have solved the problem. The clutch plate disengages without rattling and once again allows proper shifting of the transmission.
Once again, thank you for the help.

Glad to hear you figured it out and got it fixed!

And thanks for getting back and letting us all know how it turned out. 🙂 👍